Escalating Drought Vulnerability Driven by Land Use Change: Insights from a GIS-Based CA-Markov and Multi-Criteria Assessment of Future Scenarios in the Lam Ta Kong Watershed

Abstract Drought occurrence is influenced by a complex interplay of natural and anthropogenic factors, with human activities significantly shaping the frequency and severity of such events. Among these, land use change is a critical driver, as it alters the geographical and environmental characteristics that determine regional drought vulnerability. This study focuses on land use as a manageable and controllable factor in spatial development, with implications for minimizing the adverse impacts of human-induced environmental change. The research assesses the impact of land use transitions on drought vulnerability in the Lam Ta Kong watershed, emphasizing projected changes over the next decade. Drought vulnerability was evaluated using the Analytical Hierarchy Process, while future land use for 2032 was simulated using the Cellular Automata-Markov model, integrated with Geographic Information System tools. The projection was grounded in historical land use dynamics from 2000 to 2021, which revealed substantial shifts due to socio-economic growth. The transition was characterized by a decline in agricultural and forested land and a significant expansion of built-up areas. By 2032, urban areas are projected to expand by 33.11%, predominantly encroaching upon agricultural and forested lands. Current assessments indicate that 35.09% of the watershed is highly vulnerable to drought, with this figure anticipated to rise by 10.55% under future land use scenarios. High vulnerability zones are primarily concentrated in the midstream region of the watershed. These findings underscore the substantial influence of land use change on drought risk and highlight the urgent need to integrate land use planning into comprehensive drought mitigation strategies. Graphical Abstract This graphical abstract illustrates an assessment of the impacts of land use conversion on drought vulnerability in the Lam Ta Kong Watershed. The study employed spatial transition analysis using Geographic Information System (GIS) tools to identify historical land use change patterns. Building on this, the CA-Markov model was applied to project land use distribution for the year 2032. The projected scenario served as a basis for evaluating future drought vulnerability, integrating ten critical drought-related criteria, which are grouped into four factors, through the Analytical Hierarchy Process (AHP) within a GIS framework. This approach generated a spatially explicit drought vulnerability map, revealing that land use conversion substantially increases susceptibility to drought. The results underscore the urgent need for integrated land use planning and sustainable water resource management to mitigate escalating drought risks in the region.